I've just recently discovered "gramma" pads and I was wondering what people's experience has been with them. My bass has been very boomy/house shaking before and I've heard that this can help clear up the sound quality. What do you think? Are they worth the $50? (used with an Outlaw LFM-Plus)

Maybe, but not likely. All they can do is prevent vibration of the floor, caused by its resonating in concert with the sub output, from being transferred back to the speaker cabinet. It will not stop the floor from vibrating. That cabinet vibration is not the source of boom, which is usually caused by room modes. Room mode fixes and other treatments are explained here:http://www.realtraps.com/articles.htm

Depends on your situation somewhat. What kind of floor do you have? More likely another reason than what the gramma will do for you.

"I realize that somebody playing free music isn't as commercial as a hamburger stand. But is it because you can eat a hamburger and hold it in your hand and you can't do that with music? Is it too free to control?" - Don Van Vliet (aka Captain Beefheart) discussing commercial success in the music biz

Floor is carpet over concrete. And Bill, thanks for the input, I was just surprised at how many people (via reviews and another AVS member) said that gramma made a very noticeable improvement in their sub sound.

Floor is carpet over concrete. And Bill, thanks for the input, I was just surprised at how many people (via reviews and another AVS member) said that gramma made a very noticeable improvement in their sub sound.

I'm amazed at how many say cables make a difference, but there again people have been known to recover from cancer when they were only taking placebo pills, so convincing them to hear what isn't there is a small task by comparison. One thing you'll notice about glowing reviews of dubious products is that they're never backed up by data. Not that pads don't do anything, they just don't do everything that's claimed. If they did there would be measured data on the Auralex site to back it up. They do have data on their room treatment products, and those products do work as advertised. If the Gramma and SubDude (it should be named SubDud ) did what they claim it does it follows that they'd have data on that as well. There is a chart for the SubDude, but I can't for the life of me figure out what it's supposed to be measuring, and measuring speakers and room response is what I do for a living. This is what they say it does: 'Its purpose is to prevent sound from transmitting through your subwoofer to surrounding surfaces' and that's hogwash, pure and simple.

I've used Gramma for years. I like my subs on the floor but wife swears the house vibrates much less.

Only because she saw the pads there. I've actually measured in room response and also response in the basement below the living room, with and without not only 6 inches of the same foam that Auralex uses but also spikes and rubber feet. No difference.

Floor is carpet over concrete. And Bill, thanks for the input, I was just surprised at how many people (via reviews and another AVS member) said that gramma made a very noticeable improvement in their sub sound.

It will make pretty much zero difference if you're on a concrete slab. You should try a sub crawl instead. The LFM Plus shouldn't be boomy.

It will make pretty much zero difference if you're on a concrete slab. You should try a sub crawl instead. The LFM Plus shouldn't be boomy.
My sub isn't entirely inert, so my DIY solution did reduce transferred vibration in a top floor apartment setting. I think I spent $5.

That's the one instance where a pad can have a real effect, but of course the sub should be inert. If the panels vibrate energy that should be heard as sound is wasted vibrating the panels. Vibration also causes coloration, especially in the midbass and mids, as that's where most of the vibration will occur.

I've just recently discovered "gramma" What do you think? Are they worth the $50?

You should have had another poll option: definitely noticeable, but not worth the $$ they charge. I love how the Gramma quiets down the things that rattle in my room, but for what it is they charge too much. They must make a nice profit on each of them.

That's the one instance where a pad can have a real effect, but of course the sub should be inert. If the panels vibrate energy that should be heard as sound is wasted vibrating the panels. Vibration also causes coloration, especially in the midbass and mids, as that's where most of the vibration will occur.

It measures flat, I just wanted to be extra sure as at higher levels you can feel a tiny bit of vibration with your hand directly on it.

It measures flat, I just wanted to be extra sure as at higher levels you can feel a tiny bit of vibration with your hand directly on it.

A tiny bit of vibration is no biggy, and means it's in the midrange, which isn't going to cause a floor to vibrate. Ideally a sub can be played at normal volume and a glass of water atop it won't move, but not all are built to that standard by any means.

A tiny bit of vibration is no biggy, and means it's in the midrange, which isn't going to cause a floor to vibrate. Ideally a sub can be played at normal volume and a glass of water atop it won't move, but not all are built to that standard by any means.

I'm usually not trying to play anywhere near reference anyway. More of a cheap and simple DIY precautionary measure for apartment living. I'd steer clear of the commercial offerings.

A little OT, but how many hours do you think an AutoTuba build would take for someone who had put together several transmission line style cabinets in the past?

I have a suspended wood floor in my apartment - one story, attached. When I lower my foot down, the floor goes boom. The SubDude made a BIG difference in the sound. The boominess was gone. The bass was tighter and I could turn up the amp level.

I'm glad I got one. (Now, if my floor was on concrete, I wouldn't have gotten/needed one.)

I have a suspended wood floor in my apartment - one story, attached. When I lower my foot down, the floor goes boom.

That's fine if you want to jump in your room without making a lot of noise. That's not how subwoofers and sound waves work. Argue all you want, science is always right, even if you don't believe in it.

Have a suspended floor also and an LFM-1+ on a SubDude, I got it to try and stop the vibration going in through the floor and up into the sofa but it didn't really stop that, it reduced it slightly. About the same a thick piece of carpeting wood or some MDF.

Doubt it has any effect on sound quality, any differences you hear will be from it reducing the vibration of your floor / other crap.

It measures flat, I just wanted to be extra sure as at higher levels you can feel a tiny bit of vibration with your hand directly on it.

A tiny bit of vibration is no biggy, and means it's in the midrange, which isn't going to cause a floor to vibrate. Ideally a sub can be played at normal volume and a glass of water atop it won't move, but not all are built to that standard by any means.

I like my subs to splash my glass of water around on the table next to me.

In a different house I had a suspended floor and a kitchen table in the center of the that wooden floor. I had an DIY ottoman subwoofer setup I made with 4 car audio subwoofers and a couple thousand watts and that subwoofer setup actually would shake a heavy glass pitcher full of water and make it walk off the table. Another suspended floor house I lived in had a very small backyard with an in ground pool. The water in the backyard pool (about 8 foot from the back door) would actually ripple a bit due to the bass. Some folk like the tactile effect and crave more of it! Perhaps we have sensory deprivation!!!